Noninductive condenser



NOV. 26, 1940. w HAASE 2,223,173

NONINDUCTIVE CONDENSER Filed Jan. 25, 1938 3 INVENTOR WALTER ASE BY ATTO R N EY Patented Nov. 26, 1946:

UNITED STATES PATENT OFFiCE 2,223,173 NONINDUCTIVE CONDENSER many Application January 25, 1938, Serial No. 186,786 In Germany January 25, 1937 3Claims.

This invention relates to a new and noninductive electrical condenser.

The prior art condensers used in the communication technique are almost exclusively of the 5 rolled type. j Such rolled type condensers have o rectangular pieces of tinfoil are piled alternately upon rectangular pieces of mica and are clamped or bolted together so tightly that practically no air can passbetween the layers. The construction of such condensers is somewhat cumbersome, so that this arrangement notwithstanding its otherwise good electrical properties, does not satisfy the requirements of a cheap and simple construction method imder preservation of the other electrical properties that a good condenser must possess.

Another known method of constructing an electrical condenser consists of introducing thin leaves of conducting material in the folds of a ribbon made of insulating material having its folds open alternately on opposite sides, whereby the conducting leaves on one side of the folded insulator ribbon form one plate of the condenser and those on the other side of the insulator ribbon form the other plate. This construction makes for very low inductance, but similar to the rolled type condenser, it has the disadvantage, that its construction is cumbersome inasmuch as a continuous strip of tinfoil can not be used and finally the individual tinfoil leaves must be soldered together, which fact practically excludes the use of metals such as aluminum which resist soldering or can only be soldered with difficulty.

The disadvantages of the aforedescribed condenser construction can be overcome on grounds of the invention under consideration by using strips of conducting material such as tinfoil or aluminum foil placed between two strips of insulating material and then folding two ribbons made up in this manner, crosswise, one over the other.

Before folding, a portion of the material is punched out at places where the ribbon is to be folded. This facilitates at the same time, the folding of the ribbon along the edges on each side. To further simplify the construction, it is desirable to punch further holes in the metal strip as well as in the insulating strip for the introduction of pins, which will facilitate the proper alignment of the layers as they are folded one over the other. After folding, the so-constructed condenser pack is pressed tight from both sides by a clamping arrangement or by a bolt and, if necessary, the ready pack can be subsequently impregnated.

A condenser constructed according to these principles has the advantage that it has practically no induction, assuring its successful application even in short wave circuits. An additional advantage of this construction is the fact 10 that the material from which the condenser is built up can be employed in a continuous ribbon form without the necessity of cutting and aligning of the individual layers, as is, for instance, the case with mica condensers. Nor is it neces- 15 sary to resort to soldering of the conducting plates together, so that metals that resist soldering or can only be soldered with difllculty, can be employed without trouble in the described condenser construction.

Should itbecome necessary to use insulating material which can not be made up in a ribbon form, as for instance is the case with mica, then under such circumstances it may sufllce to fold the two metal ribbons crosswise m a zigzag fash- 25 ion and place the insulating plates of suitable size between the metal surfaces.

The accompanying figures illustrate the construction method of a condenser consisting of the sum of two crosswise, one over the other, folded ribbons of three layers each-(one insulating layer, one metal layer, one insulating layer).

Fig. 1 is a section of a partial condenser of this invention;

Fig. 2 is a detail of an insulating strip;

Fig. 3 is a detail of a metal foil;

Fig. 4 is an insulating strip and metal band placed one over the other;

Fig. 5 is a plan view of a complete condenser stack.

Fig. 1 illustrates on enlarged scale (actual thickness not being more than about 0.03 to 0.1 mm.) a cross section of the two folded ribbons from which a condenser is built up. The first ribbon, consisting of insulating bands i and 45 metal foil 2, is folded over in a zigzag fashion, crosswise over the band consisting of insulating bands I and metal foil 4.

Fig. 2 illustrates an example of the insulating strip i or 3, which. may be made of paper, as it would appear in unrolled and flattened out condition. At equal intervals openings 5 are punched in the paper strip in the shape of an elongated hexagon, so that only the edges indicated by the dotted line I are left solid. The

paper strip is folded along these edges. Midway between the hexagonal openings are punched round holes I through which a pin can be introduced to facilitate the proper alignment of the layers during the folding process. After the condenser is completely folded, a bolt can be introduced through the central aperture, which by means of two side plates holds the foldings pressed tight together. The dotted square I shows the electrically effective surface of the tinfoil or metal between two insulating strips in the completed'condenser.

Fig. 3 illustrates a metal foil such as 2 or 4 which can be made of rolled copper for example, as it would appear in unrolled and flattened out condition. This metal foil also has hexagonal openings l0 punched in its body, which are much narrower, however, than the corresponding openings on the paper strip, so that after the folding of the metal foil, its edges protrude on both sides of the paper strip. The square'formed by the two sides of the metal foil 2 and the two dotted lines ll again illustrate the electrically effective surface I of Fig. 2. The folding of the metal foil is accomplished along the hinges likewise marked by dotted lines I 2. In order to assure a properly aligned folding of the two ribbons, additional guide holes I! are provided which Just fit over the pins passing through them during the construction. The central opening ll punched in the metal foil between the hexagonal punchings III, has somewhat larger diameter tact with the metal foil at any place. Finally,

Fig, 4 illustrates an insulator and a metal strip placed one over the other. The reference numbers of this figure apply to the corresponding parts of Figs. 2 and 3. Fig. 5 illustrates, with.

same reference numbers as apply to the previous figures, how the condenser is built up from alternately crosswise one over the other folded layers of the two bands.

In the herein illustrated example, the ,two

bands used in the construction of the condenser, consist of separate individual strips of insulator and metal foils. It is possible, of course, to first manufacture the bands in any length consisting of a metal foil placed between two insulator foils and then proceed with theconstruction of the condensers from such bands. Naturally, a possi bility must be provided for the attaching of terminal clips. In the aforegoing example, openings were punched in the metal foil to make for small readily flexible hinges, but the same can be accomplished by simply perforating the metal foil at the corresponding bending places.

What is claimed is:

l. A noninductive electrical condenser comprising two groups of two insulating strips with a metallic strip interposed therebetween, said insulating and metallic strips each having a plurality of circular and hexagonal apertures, said circular aperturesbeing alternately arranged with respect to said hexagonal apertures, the circular apertures in said metallic strip being substantially larger than the circular apertures in said insulating strip, and the hexagonal apertures in said metallic strip being substantially smaller than the hexagonal apertures in said insulating I strip, the metallic strips of each group positioned within two of said insulating strips with the large circular aperture located on the same center line as the small circular aperture in said insulating strips, said groups being folded at the centers of 1 circular apertures to bind the folded groups 15 together.

2. A nonin'ductive electrical condenser comprising two groups of two insulating strips with a metallic strip interposed therebetween, said insulating and metallic strips each having a binrality of circular and hexagonal apertures, said circular apertures in said insulating strips being small with respect to the circular apertures in said metallic strips and the hexagonal apertures in said insulating strips being large with respect to the hexagonal apertures in said metallic strips, said large hexagonal apertures of each insulating strip being alternately arranged with respect to the small circular apertures, said large circular apertures of each metal strip being alternately arranged with respect to the small hexagonal apertures, the metallic strip of each group being positioned with its circular aperture centrally with the circular aperture in said insulating strips, each one of said groups being folded at the center position of said hexagonal aperture in the insulating, strips and arranged alternately in zig-zag fashion sothat one group is located at right angles to the other group, and clamping means passing through said circular apertures in thelnsulating strips for binding the two groups together.

3. A noninductive electrical condenser comprising two groups of two insulating strips with a metallic strip interposed therebetween, said insulating and metallic strips each having a plurality of circular apertures and approximately rectangular slots, the circular apertures in said insulating strips being small with respect to the circular apertures in said metallic strips and the rectangular slots in said insulating strips being large with respect to the rectangular slots in said metallic strips, said large rectangular slots of each insulating strip being alternately arranged with respect to the small circular apertures, said large circular apertures of each metal strip being alternately arranged with respect to the small rectangular slots, the metallic strip on each group being positioned with its circular aperture centrally with the circular aperture in said insulating strips, each one of said groups being folded at the center position of said rectangular slot in the insulating strips and arranged alternately in zig-zag fashion so that one group is located at right angles to the other group, and clamping means passing through the circular apertures in the insulating strips for binding the two groups together.

WALTER HAASE. 

